Former investors in the movie theater chain Regal Entertainment Group on Tuesday filed a petition in the Delaware Court of Chancery seeking appraisal of their shares in connection with the movie theater chain's $3.6 billion merger with U.K.-based Cineworld Group.

In the filing, hedge fund manager Blue Mountain Credit Alternatives Master Fund and its affiliates asked the court to determine the fair value of more than 6.5 million shares it said it held when the deal closed in late February. The investors had withheld their support from the merger, which created the world's second-largest theater operator and better positioned the combined company to compete with industry-leader AMC Entertainment Inc.

Regal's acquisition by the London-based Cinemark valued the company at $23 per share.

Regal, a Delaware corporation headquartered in Knoxville, Tennessee, announced the deal in early December with the support of its controller, billionaire Philip F. Anschutz, who owned about 67 percent of the company. Structured as a reverse merger, the deal required no further approval from Regal stockholders.

Cinemark investors voted overwhelmingly to approve the merger in February.

Under the terms of the deal, Regal survived the merger as a wholly owned subsidiary of Cinemark, which is owned by Israel's wealthy Greidinger family. Amy Miles, Regal's CEO, said at the time that the deal represented a “meaningful premium” and “compelling value” for Regal stockholders.

“We believe this partnership with Cineworld will enhance Regal's ability to deliver a premium moviegoing experience for customers and further build upon our strategy of introducing innovative concepts and premium amenities designed to enhance the value of our theater assets,” Miles said in a press release.

Blue Mountain investors notified Regal of their appraisal demand on Feb. 19, and the sides have been able to agree on the fair value of the petitioner's shares, according to Tuesday's court filing.

According to regulatory filings, Regal operates 7,315 screens in 561 theaters in the United States, with a primary focus on midsize metropolitan markets and suburban growth areas. Cineworld, which is incorporated in England and Wales, had 2,227 screens at 232 sites in Europe and Israel, as of last November.

The combined company operates more than 9,500 screens in 10 countries.

The petitioners will likely seek additional compensation by arguing that the deal price undervalued their shares. However, they may face an uphill climb, after recent Delaware Supreme Court decisions indicated a clear preference for deal price as the best indicator of fair value in cases that involve a robust and competitive sale process.

They are also seeking statutory interest and costs associated with litigating the appraisal action, including an award of fees for expert witnesses and attorneys.

The petition listed Samuel T. Hirzel and Elizabeth A. DeFelice of Heyman Enerio Gattuso & Hirzel in Wilmington as attorneys in the case. The petitioners are also represented by Lawrence M. Rolnick, Steven M. Hecht and Jonathan M. Kass of Lowenstein Sandler in New York.

Hirzel did not return a call Wednesday seeking comment on the filing.

An online docket-tracking service did not list counsel for Regal.

The case is captioned Blue Mountain Credit Alternatives Master Fund v. Regal Entertainment Group.